Flexible shaft drive



NW; 15, 1949 A, WYZENBEEK 2,487,915

FLEXIBLE SHAFT DRIVE Filed Aug. 16, 1947 jr/eza/ I QM @rziw,

Patented Nov. 15, 1949 FLEXIBLE SHAFTDBIYE: w

' .1i:.1 e eeew ee Applicationjiugust 16, 1947, Serial No. 768,967...

This invention relates "to a flexible shaft drive and is more particularly directed toFthe varying of the speed of a flexible-shaft relative to a driven member connected to an operating tool.

It is desired to drive-many difierenttypes of tools by means of aflexible shaft, such tools being means for brushing pots and pans, a polishing device for automobilesy a'ndfmeans'for setting screws, nuts, etc. In such operations, it is important to have a relativelythin cable and flexy ible shaft to permit the .ready manipulation, of the same; However, the buffing or brushing device often has tobe of relatively-large diameter, and such a device, in operation;exerts relatively high torque upon the flexible shaft. A flexible shaft of the character described can carry a limited torque or load, and as a-result, "in the operation of such a" tool; the shaft breaks frequently.

An object of the presentinvention is to'provide a flexible shaft structure for driving a tool, the shaft being provided with means for changing therelative speeds'of rotationofxthe tool and of the drive shaft, While at the same time providing a flexible and relatively small structure. Yet, another object is to provide a flexible shaft drive device, in'vvhich'the torque imposedupon the flexible shaft is considerably reduced while effectively driving the tool. Yet, another object is to provide a small compact structure'in which a flexible shaft is rotatedat high speed while driving a tool device at a lower speed, a resilientmember being employed'for bringing about a uniform control of the driven tool member. ...Yet, another object is to provide, in a flexible shaft structure eniployedfordrivifig"a'tool, means for speeding up or reducing the speed gf the driven member relative to the'speed of'ro'tationbf the flexible sha t .o e ob ts en es r n ill appear as the specification proceeds. f I

The invention is illustrated, a single embodiment, by the accompanying drawing, in Which-'7 T; 1 Figure 1 is a perspective viewof apparatus emdyin m i i nt n; Fla. 2, a broken l dinal sectional view; Fig. 3, a broken longitudinal sectional view of the clutch and drive mechanism;,- and Fig. 4, a transverse'sectional view, the section being takenas indicated atline 40f Fig. 2. In the illustration given,;gl lldesignates a motor which may be of any suitable type or construction, and I I designates a cable housing a flexible shaft l2. The motor cable and shaft are of well known construction and need not be described in detail herein.

3 Claims. (01. alt-1 93),

The flexible cabledrives throu hcon riectigns. which will be hereinafter'described, 91' .bufier'or cleaner device l3, asillustrated, in Fig 1, he member 13 is merely set out as illustrative, many types of tools which maybe used. ,,I.

shown more.c1early. in,Eigs,.,2..arid 5,, the cable u is secured atitsouterend to afittifig'; 1,5 threadedly connected to a tlibnlar'fiasing lemme casing I5 is provided ,withballbearing'sf. L54; 5. cured to the ball bearings. 16.183 Silevel Ll, having secured thereto a pin-.or ,stud-la;, 'rnegsfiidda extends through an inclined slofl llinj the casing l5 and also through anljouter.rotatablegsleevelui Uponrotation of outersleeve 20...ti1e' .innee;e1eeyj I1 is moved longitudinally by. rea$on..o'f.iih%il;l% clined slot l9 inethecasin 15.: Longitudinal movement of the sleeve ll,produceslongitudinal movement of the bearings I6; J; 5" In! ,1.

A tube member.2l i5 Scuredtc the innenpor tion ,of .the bearings l6,and is secured bvthegflte ting 22 to .the. inner end of thelflexi le shaft. .2, The opposite end of the tube: l',-is pltqvide,d.with a nut, 23, in {which the. end. of} a' sprin'g zllgis e; cured. The opposite end of the flexible s'pr 24 is secured within theehollow-endbf aatapered driving pin25. A; Thetubular casingwli.-isthreaded at t ward. end within. an enlarged easingoredrug}: Z The drum 26 carries the bearings 215ande28zecf-l3he drum is also provided near itscenter witha xed track 29, having-its inner walls'taperedin ard-ly and forwardly at'30.

The driven tool shaft 3l1*has"a-rforward=por4- .tion journaled within the bearing-s18 and a re aitubular portion 3 2: journaled wi'tliin th beaflhgs- 21. The drive pin"25 'extends within' the hollow portion of the III'ETnbeTBl/lb S hG'W-h Ifibre Tl y' in Fig. :2: The me'mb'erfi3l' 'i s-proviaed'="near its rearwith' an enlarged or tepereap rtian aa-rrev; ing arcuate slots 34 extending ther'ethroljigh ahd adapted to receive the tapered" roller1 bea 1:ins 35. As shown more lcle a'rlyfiii 4, the roller bearings 35 extendinwardly andoutwardly df tlie slots 34. The outer surface of the bearing s ings permitting the rollers 35 to move inwardly and 2outwardly on contact with the tapered drive pin 5.

Operation In the operation of the device, the motor I is set into operation by closing the usual switch and the shaft 2 rotates therewith. With the drive pin 25 in retracted position, the flexible shaft thus idles without causing any movement of the driven tool member 3|. When the sleeve 20 is rotated so as to advance the inner sleeve l1, bearings |6 andinner tube member 2|, the tapered drive pin 25 is brought into engagement with the three rollers 35. The flexible connector 24 enables the drive pin 25 to adjust itself to the space between the rollers 35 so as to fully engage each of the rollers with a full line contact on each roller. Even though the parts are not perfectly adjusted, or have been moved out of adjustment, the spring member 24 produces the desired contact so that the drive is accurate and complete for each of the rollers and the pin '25 has a full line contact with each roller. The clearances between the roller pins 36 and the rollers permit each of the rollers to move outwardly into engagement with the inclined'wall 30 of the seat 29 of drum 26. As the relatively small drive pin 25 rotates, it causes each of the rollers to traverse a portion of the inner seat 29, and for each rotation of the small drive pin 25, there is a proportional part rotary movement of the member'3|.' The relative speed of the member 3| is reduced because for each rotation of the shaft or pin 25 the rollers 35 traverse only a portion of the annular wall 30 and therefore produce only a partial rotation of the member 3|. Thus, the shaft l2 may be rotated at high speed to produce relatively slow rotations of the member 3| and the tool l3 carried thereby. Further, the torque or load, thus placed upon the rapidly rotating shaft, is greatly reduced.

When it is desired to stop the rotation of the tool, the operator simply rotates the sleeve 26 in the opposite direction so as to retract the inner tube H and tube 2| and thus to withdraw the tapered pin 25 from contact with the rollers 35.

It will be understood that the parts may be so proportioned as to get any desired reduction in speed or, if desired, to actually increase the speed of the driven element relative to the driving flexible shaft.

I flnd that the drive becomes unusually effective by reason of the resilient coupling member 24, which adjusts the tapered pin 25 readily and fully with respect to the three movable rollers 35 so as to produce a full line contact with each roller. This combination is efiective even though the parts have been moved out of their initial position, or even if the parts are not accurately machined for proper alignment. The flexible element enables the drive pin to make its way between the rollers and to engage each of them with a full line contact. While in the foregoing specification, I have set forth one structure in considerable detail for the purpose of illustrating an embodiment of the invention, it will be understood that the details may be widely varied by those skilled in the art without departing from the spirit of my invention.

I claim:

1. In a structure of the character set forth, a flexible shaft, a driven member adapted to be connected to a tool and having a hollow hub portion provided with slots, tapered roller bearings mounted in said slots and provided with axial openings, pins carried by said driven member and extending loosely through said openings and permitting limited radial movement of said bearings thereon, a drum enclosing said driven member and having an annular seat adapted to be engaged by said bearings, a frusto-conical member tapered for co-operation with said roller bearings and extending between said bearings for pressing the same outwardly against said drum, and a connector member joining said drive member to said flexible shaft, said connector member being resilient and capable of flexing in any radial direction' 2. In a structure of the character set forth, a flexible shaft, a casing provided with a slot disposed slantwise relative to the longitudinal dimension of said casing, a sleeve slidably mounted in said casing and connected to said flexible shaft, a rotary member carried by said casing, means connecting said rotary member and said sleeve through said slot in said casing operative to effect longitudinal movement of said sleeve upon rotation of said rotary member, a rotatable tapered drive pin, a resilient member flexible in any radial direction coupling said drive pin to said sleeve, a driven member, rotatable tapered bearings housed in said member and provided with axial openings, pins carried by said driven mercier and extending loosely through said openings permitting limited radial movement of said bearings thereon, and a drum having a tapered inner surface enclosing said driven member, said drive pin being operative when advanced by said'sleeve into engagement with said bearings to press said bearings against said drum whereby rotation of said drive pin frictionally induces revolution 0f said bearings around the inner surface of said drum.

3. In a structure of the character set forth, a flexible shaft, a driven member provided with three axially disposed slots and having a hollow central portion, tapered rollers received within said slots and mounted for limited radial movement therein, a drum enclosing said rollers, a tapered drive member engaging said rollers on the inner sidethereof and forcing them outward- 13 against said drum, means comprising a radially flexible portion connecting said drive member and said flexible shaft, and means manually operable to effect axial movement of said drive member into or out of engagement with said rollers,

' ANDREW WYZENBEEK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 417,279 Great Britain l Oct; 2, 1934 

